The present disclosure relates to stops commonly used on orthodontic archwires in combination with tooth-mounted orthodontic brackets for treatment of tooth alignment issues. More particularly, the present disclosure relates to assemblies of archwires and crimpable stops pre-threaded on the archwires.
Orthodontic treatment normally involves the application of mechanical forces to urge improperly positioned teeth into correct alignment. One common form of orthodontic treatment includes the use of orthodontic brackets that are fixed to teeth such as by a band around individual teeth or, more commonly, by mounting the brackets directly to the teeth. A resilient curved archwire is then seated in the archwire slots of the brackets. The archwires are generally attached to the brackets by ligature wires or elastic bands. Brackets of the self-ligating type include a movable cover that selectively closes the archwire slot of the brackets, eliminating the need for ligature wires or elastic bands. The movable cover is opened for inserting the archwire and then closed for retaining the archwire within the archwire slot. When a patient's teeth are out of alignment, the archwire elastically deforms to engage the brackets, thereby introducing a force that urges the teeth to move to the correct position over time.
A frequent problem observed during orthodontic treatment is that the archwire tends to move relative to the brackets under forces applied between the teeth, brackets and archwire in the oral environment. Unbalanced forces produced by the tongue, mouth muscles and chewing have a tendency to move the archwire laterally through the archwire slots of the brackets. This movement may cause a free end of the archwire to protrude from one of the brackets attached to the molars and contact gum or cheek tissue. As a result of the movement, the opposite free end of the archwire may also become disengaged from its bracket. The protruding ends of the archwire can irritate the gum or cheek tissue. Further, orthodontic treatment is disrupted by release of the archwires from the brackets.
Self-ligating brackets are constructed to retain the archwire without ligatures and elastic bands which inherently limit movement of the archwire relative to the brackets. In fact, the tooth movement promoted by free relative movement between archwire and bracket is an advantage of self-ligating brackets. Several conventional techniques are used to limit movement of the archwire in the bracket slots to prevent disengagement of the archwire from the brackets as well as to direct forces to one or more teeth. One such technique is to insert the archwire through a crimpable sleeve, such as a small diameter tube, then position the archwire within the archwire slots with the sleeve located between two adjacent brackets. The sleeve is eventually secured (crimped) to the archwire at a fixed position to form a stop. The sleeve is configured such that the sleeve cannot pass through or move beyond an archwire slot as the archwire moves in the lateral direction. In this manner, the maximum movement of the archwire is limited to the distance between the adjacent brackets. This arrangement effectively prevents the free ends of the archwire from becoming disengaged from the molars at the back of the mouth. Stops may be arranged to direct forces generated by the archwire to specific teeth.
A major shortcoming of the conventional technique described above is that the crimpable sleeve is mounted to the archwire in the field, such as a doctor's office, and usually by the dentist or a dental assistant. Archwires and crimpable sleeves are very small, making threading a sleeve onto the archwire difficult. The sleeves also have a tendency to slide off the archwire during handling and installation. The tiny sleeves are easily mishandled and/or lost.
There is a need for an improved archwire assembly that eliminates the need for field assembly and further limits the movement of the sleeve once positioned on the archwire.
There is a need for a simple, disposable tool for handling crimpable sleeves in the field.
There is also a need for an improved archwire assembly that improves the visibility of a crimpable sleeve on an archwire and facilitates manipulation of the sleeve into a desired location on the archwire.